By Lawrence Hurley

WASHINGTON (Reuters) – President Donald Trump was set to unveil his pick for a lifetime job on the U.S. Supreme Court on Tuesday as Democrats, still fuming over the Republican-led Senate’s refusal to act on former President Barack Obama’s nominee last year, girded for a fight.

Trump said on Monday he would reveal his choice to replace conservative Justice Antonin Scalia, who died in February 2016, at the White House at 8 p.m. on Tuesday (0100 GMT on Wednesday). The court is ideologically split with four conservative justices and four liberals, and Trump’s pick is expected to restore its conservative majority.

Three conservative U.S. appeals court judges appointed to the bench by Republican former President George W. Bush were among those under close consideration.

They are: Neil Gorsuch, a judge on the Denver-based 10th U.S. Circuit Court of Appeals; Thomas Hardiman, who serves on the Philadelphia-based 3rd U.S. Circuit Court of Appeals; and William Pryor, a judge on the Atlanta-based 11th U.S. Circuit Court of Appeals.

Under the Constitution, a president’s Supreme Court nomination requires Senate confirmation.

Democrats remain enraged over Majority Leader Mitch McConnell’s refusal last year to allow the Senate to consider Obama’s nomination of appeals court Judge Merrick Garland for the vacant seat, an action with little precedent in U.S. history.

Gambling that Republicans would win the presidency in the Nov. 8 election, McConnell argued that Obama’s successor should get to make the pick. The senator’s gamble paid off with Trump’s victory, but the court has run shorthanded for nearly a full year.

A Supreme Court justice can have influence in national affairs for years or decades after the president who made the appointment has left office. Some Democrats have said the Republicans stole a Supreme Court seat from Obama.

Democratic Senator Jeff Merkley vowed to pursue a procedural hurdle called a filibuster for Trump’s nominee, meaning 60 votes would be needed in the 100-seat Senate unless its long-standing rules are changed. Trump’s fellow Republicans hold a 52-48 majority, meaning some Democratic votes would be needed to confirm his pick.

“We need to fight this Constitution-shredding gambit with everything we’ve got,” Merkley said in a statement.

Trump’s appointee could be pivotal in cases involving abortion, gun, religious and transgender rights, the death penalty and other contentious matters.

McConnell on Monday warned Democrats that senators should respect Trump’s election victory and give the nominee “careful consideration followed by an up-or-down vote,” not a filibuster.

Trump, who took office on Jan. 20, said last week he would favor Senate Republicans eliminating the filibuster, a change dubbed the “nuclear option,” for Supreme Court nominees if Democrats block his pick.

Gorsuch, Hardiman and Pryor possess strong conservative credentials.

Gorsuch, 49, joined an opinion in 2013 saying that owners of private companies can object on religious grounds to a provision of the Obamacare health insurance law requiring employers to provide coverage for birth control for women.

Hardiman, 51, has embraced a broad interpretation of the constitutional guarantee of the right to bear arms and has backed the right of schools to restrict student speech.

Pryor, 54, has been an outspoken critic of the court’s 1973 landmark Roe v. Wade ruling legalizing abortion, calling it “the worst abomination of constitutional law in our history.” Conservatives are hoping the high court will back restrictions imposed on the procedure by some Republican-governed states.

(Additional reporting by Andrew Chung, Ayesha Rascoe, Lawrence Hurley and Doina Chiacu; Writing by Will Dunham; Editing by Paul Simao, Jonathan Oatis and Susan Heavey)